In such prior application there is disclosed an abrasive strip which comprises extruded nylon incorporating abrasive mineral or abrasive particulate matter homogeneously mixed therein throughout. The strip or tape of the prior application may be formed into a variety of useful abrading tools, particularly internal finishing tools. Some of the tools are formed by cutting the tape or strip to fit a variety of power drive arbors or hubs. Some of the tools are formed by heating the tape or strip followed by quenching to give the abrasive strip or elements a permanent desired curvature or configuration. In addition, the strip or tapes are scored in a manner to facilitate the handling of the strips or tapes to form various tools with the scoring being designed to promote fracture in operation of the tools so that the strip breaks apart in use into a plurality of rectangular fingers. The scoring of the strip is not easily accomplished so that controlled fracture results.
It has been discovered that the strip when extruded has a grain which extends in the direction of extrusion or along the extrusion machine axis. It has also been discovered that if the strip is scored parallel to the direction of extrusion it will fracture more readily, but fracture problems still, nonetheless, are encountered. It has also been discovered that the desired fracture may be obtained by incorporating in the scoring perforations of an elliptical or pointed configuration so that the fracture, in effect, takes place from one perforation to the next along the scoring lines.
In such prior application there is illustrated what might be termed a flap wheel made from such tape or strip. Conventionally, flap wheels are made from sandpaper flaps which are die cut to incorporate notches or holes by which the flaps are anchored into a hub. If desired, adhesive may be employed in addition to the mechanical anchor of the flap into the hub.
For rotary wheel brushes or other types of wheel tools, complex mechanical anchors are employed such as core wires about which the bristle material is folded. Such brushes are difficult and expensive to make and often require trimming at the tool face to provide a proper cylindrical work face.